Dishwashing apparatus



April 17, 1962 J. MIXON DISHWASHING APPARATUS Filed June 8, 1959 INVENTOR JOSEPH L. mx oN ATTORNEY United States Patent Ofiice 3,029,827 Patented Apr. 17, 1962 cost mechanism for the automatic admission of detergent to the washing water of a dishwasher wherein one or more preliminary power rinsing steps are carried out.

The invention is particularly adaptable to a dishwasher of the domestic type having a motor driven impeller in the bottom of the vat for circulating water upwardly and outwardly and generally in a vortex over the tableware, the latter being carried in suitable racks in the yet. In this type of apparatus, it has been proven that a rinsing step, preliminary to the washing operation substantially increases the washing efliciency as the amount of food particles circulated during the washing operation is greatly reduced; it being understood that the loose soils removed during the rinse are discharged with the rinse water. It

is generally believed that a power rinse carried out by rapid circulation of water by the impeller is superior to a simple spray because of the increase in quantity and types of food soils which the power rinse will remove from the tableware. One or more power rinses are also efiective to preheat the tableware and the washing vat with the re- The foregoing and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

The single FIGURE in the drawing is a vertical section taken through a dishwasher having the improved detergent admission mechanism applied thereto. 7

Referring to the drawing in detail, a dishwasher of the domestic type is disclosed including a vat structure 10 having side walls 11 and a bottom wall 12, the latter having a sump 13 centrally formed therein. The upper margin of the side walls 11 is provided with a resilient gasket 14 against which a removable cover 15 bears during operation of the dishwasher. The vat structure 10 may be circular or rectangular when viewed in plan, as is well understood.

Arranged within the vat 10 are upper and lower dish racks 16 and 17, respectively, which are shown in part by broken lines. These racks may be of any suitable construction and are usually formed of wires secured together for providing supports for the tableware. As the construction of wirejracks of this kind is well understood, further description is deemed unnecessary. However, it might be added that the top rack is usually employed for washingcups, odd-shaped dishes, and drinking glasses and the lower rack for fiat pieces of tableware such as dinner plates, platters, saucers, salad dishes, and also pots and pans.

Hot water is admitted to the vat 10 through a conduit 18 having a valve 19 shown, by way of example, asa solenoid operated valve connected therein for controlling the leads to a suitable point of discharge (not shown) and course, particularly acute in automatically cycled ma- 7 chines. It has been proposed to shield the detergent in a container from the rinse water, which container is automatically opened for dumpingthedetergent at the time the washing water is admitted to the vat. Such detergent admitting devices are costly, are subject to wear and corrosion in service, and their operation can be adversely affected by improper placement of tableware in the vat. Accordingly, their reliability may be questioned.

In accordance with the present invention, the automatic admission of detergent is carried out by an inexpensive device as follows. It has been found that the pattern of water discharged by a rotary dishwasher impeller varies substantially with the amount of water in the pool in which the impeller is disposed. The water projected by the impeller moves upwardly and outwardly in a vortex, the configuration or pattern of which varies with the amount of water admitted to the washer. It is, therefore, proposed to carry out the power rinse or rinses with a quantity of water less than the quantity used for the washing step which follows. Accordingly, during the power rinses, the projected water is directed through one region of the vat and, when additional water is employed for the washing step, the increased amount of projected water passes through not only said one region but an additional region also. In other words, the size of the vortex is increased. It is within this additional region that an inexpensive open cup is provided for the detergent. Accordingly, during the power rinse, substantially all of the detergent remains in the cup. But, when the vortex of water is expanded during the washing step, the detergent is washed from the cup and dissolves in the washing water.

It is a further object of this invention to control the discharge of detergent from a container within a dishwasher in accordance with changes in the patterns of the water projected within the washer vat.

flow of water through the conduit 22 may be controlled in any conventional manner.

A rotary impeller 23 is disposed centrally within the sump 13 and, during operation, projects water upwardly and outwardly within the vat in a vortex, further reference to which is made hereinafter. The impeller 23 is rotated by a vertical motor 24 secured to the bottom wall of the vat and having its shaft extending'within the vat and fixed to the impeller 23, all of which is well understood.

In the operation of a dishwasher, as described up to the present, a rinse, preliminary to the washing step, is a usually employed for the removal of some food soils from the tableware. These soils are removed from the vat 10 with the vitiated rinse water through conduit 22, after which the washing water is admitted to the vat and a detergent is dissolved therein for carrying out the washing step. It has been found that a preliminary rinse which is carried out by operating the impeller 23 for forced circulation of the body of water in the vat is more eifective for the removal of food soils than any other form of prerinse, such as, the spraying of the tableware by water as it is admitted to the vat. This form of rinse which is carried out by the impeller is generally called a power rinse and presents a problem of admitting detergent particularly in automatic cycle machines where the attendant is not present to manually carry out this step. As set forth above, mechanically operated detergent containers have been proposed for dumping detergent automatically in the washing water, but these mechanisms are expensive and subject to malfunction and failure in service.

In accordance with the present invention a simple, inexpensive device for admitting detergent to the washing water, following a power rinse, is provided. In a rotary impeller type of washer, as disclosed, the pattern of the projected water varies with the quantity of water admitted to the vat. For example, in the embodiment shown, with about one gallon in the vat, the projected vortex of water moving upwardly and outwar ly in the vat is represented by the broken line A. At this time, the annular region of vat between line A and the side and bottom walls 11 and 12 contains the projected vortex of water and the remainder of the vat is substantially devoid of the rapidly moving particles of water. This is the prevailing condition during a power rinse step and it will be observed that the rinse water is directed primarily over the were in the lower rack which, usually, carry the most soils.

For the Washing step, approximately two gallons of water are admitted to the vat and the annulus of projected water is represented by line B. Now, the annulus of projected water occupies the region of the vat between line B and the side and bottom walls 11 and 12 of the vat. At this time, an additional annular region represented by character C and between lines A and B has been added to the region prevailing during the power rinse. Within this additional region C, an open container or cup 25 for detergent is disposed. The container may be snugly fitted within a wire ring 26 that is carried by a wire 27 suitably fixed, as by welding, to a portion of the upper rack 16. The cup 25 may be readily removed from the ring 26 for cleaning but may be filled with detergent while assembled in the ring 26. Where a granular detergent is employed, the cup may be formed with a foraminous body to permit drainage. An imperforate cup might be used for liquid or granular detergent since the detergent will be floated out of the cup 25 when the latter is subjected to water moving through the region C.

A few droplets of water may contact the detergent in cup 25 during the power rinse as a result of water splashing from ware in the lower rack 17. It has been observed that the amount of detergent which is dissolved or washed from cup 25 during this period is so small as to have no detrimental effect on the subsequent washing operation.

A selective control of the admission of relatively small and large quantities of water to the vat for the power rinse and washing operations may be effected in any well-known manner. Preferably, the period of time that the solenoid operated valve 19 is opened is varied by means of a suitable timer control, such as that described in Patent No. 2,575,707 to E. K. Clark. If desired, suitable adjustable water level control devices, now in common use, may be employed for this operation.

From the foregoing, it will be apparent that improved means for dispensing detergent in a dishwasher having a preliminary power rinse is provided. The detergent container having no adjustable parts will be reliable in operation. The location of the container in the vat provides ready access for cleaning or servicing.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof.

What is claimed is:

1. In a dishwasher, the combination of a vat, means supporting dishes to be cleaned within the vat, means for sequentially admitting relatively small and large quantities of water to the vat for effecting, respectively, a preliminary rinse and a washing operation, water projecting means for directing said small quantity of water through a region of the vat and over the dishes for providing said preliminary rinse, said last named means being effective to project said larger quantity of water through said region of the vat and through an additional region thereof for providing the washing operation, an open container for detergent disposed within said additional region of the 'vat and means motivating said water projecting means.

2. In a dishwasher, the combination of a vat, means for supporting dishes to be cleaned within the vat, means for sequentially admitting relatively small and large quantities of water to the vat, an impeller disposed adjacent the bottom of the v'at for projecting water upwardly and outwardly within the vat and over the dishes; the pattern of the water projected by the impeller with said relatively small quantity of water in the vat defining a vortex occupying one region of the vat, the vortex of projected water when a relatively large quantity of water is contained in the vat being enlarged to occupy an additional region of the vat, and an open container for detergent arranged within the vat in said additional region thereof.

3. In a dishwasher, the combination of a vat, means supporting tableware to be cleaned within the vat, means for sequentially admitting relatively small and large quantitles of water to the vat for effecting, respectively, a preliminary rinsing step and a washing operation, an impeller disposed adjacent the bottom of the vat for circulating said smaller quantity of water through one region of the vat during the rinsing step, said impeller effecting circulation of the larger quantity of water through said one region of the vat and an additional region thereof during the washing operation, and an open cup for containing detergent and disposed in said additional region of the vat; the construction and arrangement being such that the detergent is undisturbed, substantially, during the rinsing step and is washed from the cup by the additional circulation of water during the washing operation.

References Cited in the file of this patent UNITED STATES PATENTS 

